Industry is constantly seeking new and/or improved materials and methods of providing sound and noise reduction in a variety of applications. Materials that exhibit sound absorption characteristics are often employed as a way to provide noise reduction in a wide range of industrial, commercial, and domestic applications. It is often desirable to reduce noises of machinery, engines, and the like. For example, in automotive applications, it may be undesirable for a passenger to hear noises coming from the engine compartment of the vehicle.
Traditional sound absorbing materials may have a low temperature resistance, and therefore cannot be installed in areas where the material would be exposed to heat, as they are not capable of withstanding high temperatures. In applications where there are high levels of radiant heat generation, such as within the engine compartment of an internal combustion engine where exhaust and turbo charger components generate significant amounts of thermal radiation, there is a risk that the material will absorb significant amounts of heat and sag, melt, or even catch fire. Certain sound absorbing materials have also been shown to degrade upon exposure to moisture and other engine/powertrain fluids. These sound absorbing materials, therefore, cannot be used alone in all areas where sound absorption is desired.
Therefore, it is desirable to provide improved noise reduction in a variety of applications, such as through improved sound absorption materials. There is also a desire for noise reduction, such as through sound absorption materials that can withstand higher temperatures, such as in applications of high levels of radiant heat generation, that can provide localized heat reflection, or both.
Accordingly, the present teachings provide for a nonwoven material that meets the desires stated herein through the use of an acoustic material having one or more acoustic composite layers (e.g., a lofted porous bulk absorber), a facing layer (which may be permeable, metalized, metallic, or a combination thereof). The present teachings also provide for the method of assembling this acoustic material.